[Clinical value of cleaved lymphocytes in assisting the diagnosis of pertussis in children].

Objective: To study the value of cleaved lymphocytes in peripheral blood smear in assisting the early diagnosis of pertussis.

Methods: Nasopharyngeal swabs and peripheral blood samples were collected from 107 children with pertussis-like disease. PCR-flow fluorescent hybridization was used to detect the nucleic acids of Bordetella pertussis. Based on the detection results, the children were divided into two groups: pertussis (n=52) and non-pertussis (n=55). According to age, the pertussis group was divided into two subgroups: <1 year old (n=42) and ≥1 year old (n=10). According to disease severity, the pertussis group was divided into another two subgroups: mild (n=45) and severe (n=7). An automatic blood cell analyzer was used to determine peripheral blood cell counts. Wright's staining and peroxidase staining were used to observe and count cleaved lymphocytes under a microscope.

Results: Cleaved lymphocytes in peripheral blood were round with small cytoplast, less cytoplasm and cleaved or lobulated nuclei. According to the negative peroxidase staining results, these cells were confirmed as lymphocytes. Compared with the non-pertussis group, the pertussis group had significantly higher leukocyte count, lymphocyte percentage, platelet count, and percentage of cleaved lymphocytes (P<0.001). For the children with pertussis, the <1 year old subgroup had significantly higher lymphocyte percentage, platelet count, and percentage of cleaved lymphocytes than the ≥1 year old subgroup (P<0.05). The severe subgroup had slightly higher leukocyte count, lymphocyte percentage, platelet count, and percentage of cleaved lymphocytes than the mild subgroup (P>0.05).

Conclusions: The detection of cleaved lymphocytes combined with peripheral blood cell counts provides a new option for the early diagnosis of pertussis in children.